Appeals court allows House Democrats to continue lawsuit for Don McGahn testimony

• "The Committee ... has shown that it suffers a concrete and particularized injury when denied the opportunity to obtain information necessary to the legislative, oversight, and impeachment functions of the House," the opinion says.
• "Indeed, the ordinary and effective functioning of the Legislative Branch critically depends on the legislative prerogative to obtain information, and constitutional structure and historical practice support judicial enforcement of congressional subpoenas when necessary," it adds.

The big picture: McGahn was one of the most important witnesses in Robert Mueller's investigation. He appears on 66 pages of the Mueller report and played a central role in some of its juiciest revelations, including the fact that President Trump once asked him to fire Mueller.

Catch up quick: Democrats on the House Judiciary Committee have fought a lengthy legal battle to question McGahn regarding Trump's alleged attempts to obstruct justice.

What's next: The matter now returns to a three-judge panel for consideration on other legal issues, per the AP.

• Worth noting: Judge Thomas Griffith noted in his dissent that "the chances that the committee hears McGahn’s testimony anytime soon are vanishingly slim," since the current House session ends at the start of January.

Read the ruling.

Go deeper: Former White House counsel Don McGahn off the record